1. Field of the Invention
The present invention relates to a water cooled internal combustion engine for a vehicle, wherein a crankcase cover for covering a lateral side of a crankcase is attached to the crankcase that forms a portion of an engine main body mounted on a vehicle body frame and that rotatably supports a crankshaft. A pump driving shaft, operated by power transmitted from the crankshaft, is rotatably supported on an axis parallel to the crankshaft by the crankcase. A water pump to be driven through the pump driving shaft has an axis of rotation that is coaxial with the pump driving shaft and is arranged on the crankcase cover.
2. Description of Background Art
A water cooled internal combustion engine for a vehicle is known that includes a pump case for a water pump to be driven by power transmitted from a crankshaft which is rotatably supported by a crankcase that is composed of a crankcase cover that covers the crankcase and rotatably supports a pump shaft of the water pump and of a pump cover that is fixedly attached to the crankcase cover from the outside. See, Japanese patent laid-open publication No. 2007-315199.
However, the engine disclosed in Japanese patent laid-open publication No. 2007-315199, has a construction wherein after attaching a crankcase cover to a crankcase, a pump cover is fixedly attached on the crankcase cover from the outside. Accordingly, tightening members arranged on an outer periphery of the pump cover remain exposed outside whereby there is a possibility of injuring an external appearance. In addition, there is a possibility that the internal combustion engine is increased in size in the direction along the crankshaft. More particularly, in the water cooled internal combustion engine to be mounted on a straddle type vehicle such as a two-wheeled motorcycle and the like, it is required that the size in the width direction of the internal combustion engine should be made to be compacted so as to obtain a good straddling comfort of a rider.